The present invention relates to image scanners, and particularly to portable high speed image and optical character recognition scanners that can flexibly handle intermixed documents of varying sizes.
Scanners of this type have been available for a number of years. The main functional components are the document transporter, the camera, the transport sensing and control, the image capture and processing, and the operator interface for job control. Typically, an analog to digital converter (A/D converter) provides a data interface for the sensors and the electromechanical devices of the transporter. A general-purpose computer (personal computer, or PC) contains software programs for performing the operator interface, interacting with the A/D converter to identify physical and positional aspects of the document, and controlling the timing of the camera, as well as special dedicated boards for image capture and control. A multiplicity of distinct, fixed-logic controller boards interact with the A/D converter to implement transport control logic through respective electromechanical devices.
The present inventors have identified two main disadvantages to the conventional scanner system as described above.
First, there is a high cost in hardware, programming, and maintenance for providing a multiplicity of distinct fixed-logic controller boards, each associated with one of a multiplicity of transporter related control functions to be performed by the system. The chips on each board must be programmed and the board fabricated. Moreover, if an operational problem is encountered by the user, the diagnosis often requires inspection of several boards to find the problem. The service provider must maintain a large number of boards in inventory, so that whichever one of the multiplicity of boards that is defective, can be readily replaced.
Second, there is programming duplication because many of the physical and positional aspects of the document derived from the A/D converter must be used in both the PC and the controller boards, but the programming must be performed independently as between the software based PC and the fixed-logic of the controller boards. The further consequence is that any improvement in software processing capability that can be readily implemented in or by replacement of the PC, cannot be readily implemented in parallel in the fixed-logic boards.